package com.atguigu.springcloud.OrderMain80.lb;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @Author: 王丹
 * @Date: 2021/3/28 0028 8:25
 * @Description:
 */
@Component
public class MyLB implements LoadBalancer {
    private AtomicInteger atomicInteger = new AtomicInteger(0);
    public final int getAndIncrement(){
        int current;
        int next;
        do {
            current = this.atomicInteger.get();
            next = current >= Integer.MAX_VALUE ? 0 : current + 1;
        } while (!this.atomicInteger.compareAndSet(current, next));
        System.out.println("****next: " + next);
        return next;
    }
    //负载均衡算法：rest接口第几次请求数 % 服务器集群总数量 = 实际调用服务器下标，每次服务重启动后rest接口计数从1开始
    @Override
    public ServiceInstance instance(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement()%serviceInstances.size();

        return serviceInstances.get(index);
    }
}
